robocontrol_programmingfandomcom-20200214-history
Wireless Control
Wireless Robotic Control What is wireless control? Unlike wired or autonomous robotic control, wireless control allows the robot to move freely without being connected to something while also allowing someone to control what it does with the push of a button. Wireless control is the most commonly seen form of robotic control, although autonomous robotic control is the typical end-goal for the scope of robotics. Overall, wireless control is easy to understand but a little tricky to execute as there are several different ways to control a robot wirelessly as well as obstacles to overcome in doing so. The goal of this guide is to help you understand the different types of wireless robotic control as well as the positives and negatives of each one. Additionally, this guide offers ways to improve these wireless emissions and explains some of the legal aspects of wireless control as well. Enjoy! Different Types of Wireless Control [1+ 2] Infrared ' Often seen as the first step in wireless control for beginners, infrared control is the easiest control method to use. Infrared controllers use infrared wavelengths to send a transmission to a infrared receiver on the robot. A microcontroller then interprets the coded information in the receiver and sends that command to the robot. Infrared wavelengths are longer than those of visible light, so the light from the controller is invisible to the human eye. However, because the wavelengths are longer, the controllers require line of sight and any obstacle that comes between the controller and the receiver will block the signal. Fortunately, due to its ease of use and understanding, most remote controllers in the market can be used to control the robot! Pros: Fairly inexpensive and easy to understand Most remote controls sold today can work as controllers for the robots Cons: Line of sight control Distance from controller to robot is limited to a short distance '''Radio Frequency Modules ' Radio Frequency Modules are typically associated with RC (Remote-Controlled) vehicles, but they can be used in robotics as well! RF communication consists of a transmitter and a receiver with the receiver being attached to the controlled vehicle. The transmitter sends out electromagnetic waves at a certain frequency and pattern and the receiver intercepts, understands, and executes this command as told. In order for the receiver to understand the command, however, the transmitter and receiver need to be matched or paired before hand or a transceiver must be used (transceiver both sends and receives information simultaneously). Because of this, RF communication is a little trickier to understand and the commands are simplified to allow easy transmission. However, the signal send out from the receiver can reach a considerable distance and penetrates through most objects! Pros: Omnidirectional Signals that can penetrate through most objects Signals can reach much farther distances than Infrared signals Cons: Low data rate that limits the complexity of commands The transmission frequencies can be shared and cause confusion with pairing to receivers 'Bluetooth ' Bluetooth waves are a form of RF communication that have more specific protocols for data transferral. Just like RF modules, Bluetooth allows the user to send a transmission to a receiver without being impeded by obstacles. While the range is a lot smaller for Bluetooth communication, larger amounts of data can be shared between the transmitter and the robot, allowing for more complex commands! The best part about bluetooth communication, however, is its ease of use as most phones and computers already are equipped with bluetooth capability. While some interface customization may be necessary on the pc or mobile device to control the robot smoothly, bluetooth control is definitely an easier to use method of RF communication. Pros: Any bluetooth-enabled device can be used as a controller (computer, cell phone, etc.) Larger amounts of data can be shared Omnidirectional signals that can penetrate and avoid most objects Cons: Devices need to be paired with the receiver much like RF Modules The range of control is limited to roughly 10 meters 'Wi-Fi ' The newest method of wireless robotic control is internet communication through Wi-Fi. With Wi-Fi communication, data is sent through a wireless internet connection from a device, such as a remote or phone, to the robot's receiver where the data is interpreted and executed. This method of wireless communication is very clear and easy to understand but it does have its drawbacks. Mainly, in order to have Wi-Fi communication you need to have Wi-Fi through purchasing a router. You'll also need to connect the robot's receiver and the device you're controlling the robot with to the same router and, if the commands are pretty complex, you might need to alter the bandwidth available through the router. Despite these drawbacks, there's no limit to the range of controlling the robot, the data transfer speeds are very quick, and video camera feedback/reception is an easy to achieve possibility through Wi-Fi. Pros: Robots can be controlled from anywhere as long as they are within range of a router High Data transfer rates makes for speedy communication Cons: More programming may be required to achieve communication Some complex commands may require updated bandwidth from the router '''Cellphones/DTMF Originally created for human to human communication, the cell phone has recently been used by several engineers to control robots wirelessly. This is different from bluetooth communication as a cell phone is connected to the robot and, through communication between the pairs of cell phones, messages are sent without the use of radio frequencies. The cell attached to the robot receives a dial tone of a button pressed from the control cell phone and a decoder breaks down the dial tone into a binary code it can understand. This dial tone is referred to as a Dual Tone Multi Frequency (DTMF). When the robot receives the DTMF, the decoder correlates a value and tells the motor or sensors what to do accordingly. For a detailed description of how DTMF communication works, check the table below. Cell phone communication is fairly rough and doesn't use waveforms to communicate, but as long as both phones are connected to a cellular network, robot control can occur at any range! Transfer rates are dependent on the strength of the cellular network, but they do tend to be fairly quick. Unfortunately, due to the laws and regulations surrounding cellular communication as well as the service not being free, cellular communication is not recommended for beginners! Pros: No limit to the range of control as long as a cell network is available Cons: Cellular frequencies are regulated which means research and an understanding of the laws are required Cellular services are not free and will require the purchase of a cell network Communication system is still fairly clunky and not laid out well for robotic control How do I improve my wireless signal? http://robotsforroboticists.com/long-distance-wireless-communications-antennas/ 3 That is a very good question but, just like there are multiple ways to control your robot, there are also multiple ways to improve upon your signal strength. Loss Reduction The easiest way to boost your signal is to reduce the amount of signal lost in transference. This can be achieved by maintaining the connectors, transmitters, and receivers. Minimize the amount of each connector that you use to avoid connecting to multiple connectors at the same time. Additionally, cleaning your connectors, transmitters, and receivers on a regular basis stops dust from settling and potentially blocking the connection between the controller and the robot. Antenna While it may look outdated and clunky, antennae really help to improve the strength of the signal sent from a controller or received by the robot. There are different types of antenna such as omnidirectional, directional, shortened, and more that can either help improve or focus the signal's transmission path. If an antenna is attached and signal doesn't improve, try moving obstacles out of the way to improve the Line of Sight between the transmitter and the receiver. Signal Amplifiers This method can only truly be applied to radio frequencies, but if you're using RF communication as your wireless method, this may be the best solution for you! Signal amplifiers inject more power in the controller to improve the signal's strength and give it a much better range and data transfer speed. While the amplifier itself may need power to boost the power, the results don't lie! Final Thoughts on Wireless Communication As you can see, there are many different ways to control robotics wirelessly and each method used really depends on the aptitude of the user. While it is entirely up to you which method you use, hopefully the information provided here can help you to understand the processes that run the communication between a controller and a receiver as well as allow you to make an educated decision on which one best suits your individual goals! References: # http://www.robotshop.com/blog/en/how-to-make-a-robot-lesson-6-controlling-your-robot-2-3688 # http://www.robotplatform.com/knowledge/communication/wireless_communication.html # http://robotsforroboticists.com/long-distance-wireless-communications-antennas/ Category:Wireless Category:Control Category:Wifi Category:Bluetooth Category:Infared Category:Cellular Category:Radio Frequency Category:RF Category:Technology Category:Robotics Category:Programming Category:Business